Accurate PCB fabrication begins with a complete and standardized data package. The preferred format is Gerber Extended (RS274X), which should be configured as the default output in the CAD system. This format is used directly for artwork plotting and avoids the interpretation issues that can arise with other file types.
Older Gerber formats that rely on separate aperture lists can still be used, if necessary, but they introduce additional risk. Loading delays are common, and incorrect aperture entries may lead to corrupted data that could compromise the entire order.
ODB++ is also accepted and should be delivered as a single compressed file, typically in a .TGZ format. While DXF files are accepted, they require conversion to Gerber for photo plotting, which introduces opportunities for error and additional processing time.
Laser Direct Imaging
Laser Direct Imaging (LDI) is an advanced photolithography process used in printed circuit board (PCB) manufacturing to transfer circuit patterns directly onto photoresist-coated panels without the need for traditional film artwork.
By using high-precision laser technology, LDI improves image accuracy, registration, and feature resolution while reducing defects caused by film distortion. This process is particularly beneficial for high-density interconnect (HDI) and fine-line PCB designs, where tight tolerances and precise alignment are critical to achieving reliable electrical performance.
Necessary Files to Manufacture Your PCB
A complete PCB data package must include all files required to define the physical and electrical structure of the circuit board. Missing or incomplete files can delay processing and increase the risk of manufacturing errors.
Example of PCB Fabrication Data Package
Required data files include:
- All copper layers
- All solder mask, silkscreen, and paste layers
- A complete circuit board outline, including cutouts and slots where applicable
- Excellon ASCII drill files for each drill cycle (through, blind, buried, slotted), including tool codes and diameter information
- One or more fabrication drawings or equivalent documentation
Providing this full data set ensures the fabrication process can begin without unnecessary clarification or rework.
Information to Include in Your Circuit Board Fabrication Instructions
Fabrication drawings and notes define the manufacturing requirements and must clearly communicate all critical parameters. This information ensures that the PCB is manufactured according to design intent and minimizes ambiguity during production.
Key fabrication details include:
- Hole sizes with tolerances and plating status (PTH or NPTH)
- Circuit board outline dimensions with tolerances
- Hole-to-edge and feature-to-edge dimensions
- Finished copper weights for internal and external layers
- Final PCB thickness, including tolerances and measurement criteria
- Surface finish requirements
- Solder mask specifications
- Silkscreen requirements
- Additional requirements such as impedance control, dielectric thickness, or via plugging
- Technical contact information for clarification
- Panelization details if boards are provided in assembly panels
Clear and complete fabrication notes reduce the likelihood of errors and ensure consistent results.
Acceptable PCB Fabrication Drawing File Formats
A range of file formats can be used to communicate PCB design and fabrication data. While several formats are acceptable, some require additional processing before they are ready for production.
Accepted formats include:
- Gerber RS274X (.gbr, .pho)
- PDF (.pdf)
- AutoCAD formats (.dwg, .dxf)
- HPGL plot files (.hpg, .plt)
- Image files (.jpg, .gif, .tif)
- ODB++ (.tgz)
- Documentation files (.doc, .txt, .rpt)
DXF files in particular are not production-ready and require conversion, which may introduce errors and result in a one-time data preparation charge. These files are also not suitable for quick-turn requirements and can add approximately one week to the overall schedule.
In cases where other file formats are available, they may be reviewed prior to order placement to determine compatibility.
Data Completeness and Quotation Accuracy
Accurate PCB quotations depend on providing a complete and well-structured data package. Using Gerber RS274X as the primary format streamlines processing and reduces the risk of misinterpretation.
Incomplete, outdated, or improperly formatted files increase the likelihood of delays, added costs, and potential fabrication errors. Ensuring that all required layers, drill data, and fabrication notes are included upfront allows for faster quoting and a smoother transition into manufacturing.
For more information check out our section on PCB design and layout or download our free circuit board design guide.
Summary
Accurate PCB quotations depend on providing a complete and properly formatted data package. Gerber RS274X files are the industry standard, while formats like ODB++ and DXF are acceptable but may cause delays or added costs. A comprehensive data set should include copper, solder mask, silkscreen, drill, and fabrication drawings, along with clear fabrication notes specifying tolerances, finishes, thicknesses, and special requirements. Supplying all necessary files and details upfront ensures smooth processing, avoids costly errors, and shortens lead times.
Key Takeaways
- Gerber RS274X is preferred: This format eliminates interpretation errors and ensures faster, more accurate processing.
- Incomplete or outdated files cause delays: Old-style Gerber or DXF files may require conversion, preparation charges, and longer lead times.
- A full data set is essential: Copper, solder mask, silkscreen, drill files, and fabrication drawings must all be included to start manufacturing.
- Fabrication notes guide production: Details like hole sizes, tolerances, plating status, copper weights, finishes, and mask/silkscreen requirements prevent errors.
- Accepted file formats are broad: Gerber, ODB++, PDF, DWG/DXF, HPGL, image files, and readme documentation are all usable, but Gerber RS274X remains the most efficient choice.
